That reminds me - when my grandfather used to tickle me he'd say "GIDDY GIDDY GIDDY!" This was when I was a LITTLE boy, so it was OK, not some sicko weirdo thing he did last week or anything like that. It was a very abbreviated way of saying "I'm gonna gitcha, gitcha gitcha" - the phrase devolved to "Giddy giddy giddy!"